Reference may be made to the following U.S. Pat. Nos. of interest: 2,510,514; 2,712,454; 3,275,025; 3,403,887; 3,536,296; 3,773,291; 3,779,511 and 3,883,113; 4,103,868; 4,140,149, 4,342,444; 4,465,259; 4,696,323.
Control valves for the control of fluids in the production of pharmaceuticals, specialty chemicals, and sanitary applications require precision flow control, reliable sterilization, easy cleaning of parts in contact with the fluid, as well as the usual desired valve characteristics of ease of maintenance and being economical to manufacture. While some of the above mentioned patents may meet one or more of the desired characteristics for such a fluid control valve, none meets all of them.
Accordingly, it is desired to provide a fluid control valve having precision flow control, easy sterilization, cleanability and maintenance, and which also is reliable in operation and economical to manufacture.